AWS IAM Deactivation of MFA Device

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AWS IAM Deactivation of MFA Device

Detects the deactivation of a Multi-Factor Authentication (MFA) device in AWS Identity and Access Management (IAM). MFA provides critical protection against unauthorized access by requiring a second factor for authentication. Adversaries or compromised administrators may deactivate MFA devices to weaken account protections, disable strong authentication, or prepare for privilege escalation or persistence. This rule monitors successful DeactivateMFADevice API calls, which represent the point at which MFA protection is actually removed.

Rule type: query

Rule indices:

filebeat-*
logs-aws.cloudtrail-*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-6m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

Domain: Cloud
Data Source: AWS
Data Source: Amazon Web Services
Data Source: AWS CloudTrail
Data Source: AWS IAM
Resources: Investigation Guide
Tactic: Impact
Tactic: Persistence

Version: 213

Rule authors:

Elastic
Austin Songer

Rule license: Elastic License v2

Investigation guide

edit

Triage and analysis

Disclaimer: This investigation guide was created using generative AI technology and validated for accuracy and relevance. Always tailor the steps to your organization’s environment and operational context.

Investigating AWS IAM Deactivation of MFA Device

This rule detects successful deactivation of a Virtual MFA device in AWS IAM. Deactivation removes MFA enforcement from an IAM user, significantly lowering account resilience against credential theft or unauthorized access. Since MFA devices must be deactivated before deletion, this represents the earliest and most critical opportunity to detect potential account compromise or persistence activity.

For more information about using MFA in AWS, access the official documentation.

Possible investigation steps

Identify the actor and context
Review aws.cloudtrail.user_identity.arn and aws.cloudtrail.user_identity.access_key_id to determine who initiated the deactivation.
Check whether the actor typically manages MFA or has the IAM permissions to perform such actions.
Review user_agent.original to confirm if the operation was performed via the AWS Console, CLI, or SDK.
Review the source and location
Investigate source.ip and source.geo fields for unusual origins or unrecognized locations.
Determine if this request originated from known automation infrastructure, internal IP ranges, or a personal endpoint.
Correlate with other related activity
Look for preceding API calls such as ListMFADevices, GetSessionToken, or ListUsers, which may indicate reconnaissance or IAM enumeration.
Search for subsequent DeleteVirtualMFADevice calls to confirm whether the deactivated device was later deleted — a common follow-up action.
Check for any privilege changes, credential creations (CreateAccessKey, AttachUserPolicy), or unexpected login attempts following the deactivation.
Validate authorization
Confirm with IAM or security administrators whether the action was part of an authorized device rotation or remediation.
If not documented or approved, escalate as a potential credential compromise or persistence attempt.

False positive analysis

Legitimate device rotation
When replacing an MFA device, AWS requires deactivation of the existing device before the new one can be enabled.
Administrative maintenance
IAM administrators or automation pipelines may deactivate MFA as part of account management or recovery workflows.

Response and remediation

Containment
Re-enable MFA for the affected IAM user (EnableMFADevice) or temporarily disable their login access until legitimacy is confirmed.
Revoke temporary credentials or tokens associated with the actor to prevent further misuse.
Investigation and scoping
Review CloudTrail history for additional IAM configuration changes or access key creation events tied to the same principal.
Determine whether sensitive resources were accessed after MFA removal.
Identify whether multiple users had MFA devices deactivated in a short timeframe — an indicator of broader compromise.
Recovery and hardening
Require MFA for all privileged IAM users and enforce it using service control policies (SCPs).
Enable GuardDuty or Security Hub findings for IAM anomaly detection related to account takeover or configuration changes.

Additional information

Rule query

edit

event.dataset: aws.cloudtrail
    and event.provider: iam.amazonaws.com
    and event.action: DeactivateMFADevice
    and event.outcome: success

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Impact
- ID: TA0040
- Reference URL: https://attack.mitre.org/tactics/TA0040/
Technique:
- Name: Account Access Removal
- ID: T1531
- Reference URL: https://attack.mitre.org/techniques/T1531/
Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/
Technique:
- Name: Modify Authentication Process
- ID: T1556
- Reference URL: https://attack.mitre.org/techniques/T1556/
Sub-technique:
- Name: Multi-Factor Authentication
- ID: T1556.006
- Reference URL: https://attack.mitre.org/techniques/T1556/006/

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